Fixing the MicroHD boot loop

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Glad you got it back up and running. Did you order a pre-made cable or make one?
 
Glad you got it back up and running. Did you order a pre-made cable or make one?

I ordered a cheap one off of Amazon for something like two dollars. The pins on the end that need to connect to the micro were too big, but I just used the connector from the first cable that I'd made that didn't work. Replacing the UDF fixed it and then I loaded the firmware on GeoSatPro's site. Do you know if that's the latest firmware?
 
Please Help Larry1! or Others

The link to your RS232 to TTL cable is showing"file not found"
I want to build that cable to fix the boot loop defect.

I have a computer running XP with Rs232 .....and a few MAX232 ? Chips somewhere. ( built a previous CAT cable for my ham rig before)

Does XP have the driver already installed?
I downloaded GhPMSD file etc... Will it prompt me through ordo I have to use the ALI editor? A set by step instruction would entice. Many links on this group show "file not found " so if it's been posted b4 it's likely gone

Email me direct if you can
Tnx es 73
Greg
Ps- Unfortunatly in Toronto, the oldy micro had dealer sells them sans warranty!
 
Ok- found many typical RS232 to TTL cct on the web...i would think most whould work ?

But I still have questions about doing the "Flash" and step by step for uploading new firmware ...
Thanks
Greg
 
Greg I was looking through old files and I think this is what you seek: See attached PDF.
This is the drawing Larry1 made.
You will need to use the Ali editor. Maybe others will chime in, been awhile since I did it.
 

Attachments

  • RS232_TTL_MicroHD.pdf
    129.9 KB · Views: 156
Thanks Micheal...VA3VFO hr.....
Yes that's the cct..he used the MAX202 .Other ccts seem use the MAX232..I belive they only require differnt capacitor values , but I think either TTL converter should work in duplex.

OK on needing to use the Ali editor..
If it is a plain text editor, I am not sure how to do the overwrite commands etc..
Maybe someone can explain or maybe it will be self evident when I run the editor ( self prompting?) ...I'll see what I can find via Google on how to actually instruct for the re- fash.

Any input is appreciated!

You would think Geosat would have step by step instructions on their site with this being such a common problem :-(

Tnx
Greg
 
Please Help Larry1! or Others

The link to your RS232 to TTL cable is showing"file not found"
I want to build that cable to fix the boot loop defect.

I have a computer running XP with Rs232 .....and a few MAX232 ? Chips somewhere. ( built a previous CAT cable for my ham rig before)

Does XP have the driver already installed?
I downloaded GhPMSD file etc... Will it prompt me through ordo I have to use the ALI editor? A set by step instruction would entice. Many links on this group show "file not found " so if it's been posted b4 it's likely gone

Email me direct if you can
Tnx es 73
Greg
Ps- Unfortunatly in Toronto, the oldy micro had dealer sells them sans warranty!
The cable I have now I have varied slightly from the drawing posted by KE4EST in that instead of using the power from the MicroHD, I used a 9 volt battery connected to a 7805 voltage regulator to provide the 5 volt source for the MAX chip. This eliminated the need for the connection to pin 3 on the MicroHD.
MAX232 chips work fine, just see the pdf page 10 and 11 from
www.ti.com/lit/ds/symlink/max232.pdf
for the proper caps and connections for that chip. (the value of the cap changes from the max202 to the max232, you can use a 16 Volt cap where a 6.3 Volt cap is specified The voltage rating is the maximum voltage specification, they will work fine with less voltage)
If you have difficulties finding parts, Sayal in Markham should have what is needed.
For connection to the MicroHD, old CD-Roms used the same connector for the internal audio cable.
 

Attachments

  • MicroHD_serial_cable.pdf
    1.1 MB · Views: 138
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I used this:
http://gotcband.com/collections/cables/cable
mhd_7b32d8b8-3971-4e8a-8cf9-e9b2274e21dc_large.jpg
 
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